Very odd issue indeed. Flash Plugin - Keep it up to date and troubleshoot problems click this link and read threw how to uninstall it and reinstall.

You could also try new Profiles - Where Firefox stores your bookmarks, passwords and other user data to see if something is corrupting the plug-ins report.

Adobe Flash Plugin 11.3.7.0 is an extension known to be malware while Shockwave Flash 10.3 r183 is a plugin that is used to play Flash videos.

See Troubleshoot Firefox issues caused by malware.

So, since its malware, and it's disabled I shouldn't worry about it? malwarebytes doesnt show up anything :/

This malware is composed of one executable file and one extension. Although you disabled the extension, the executable file still does bad things.

So follow all the steps in the article about malware above.